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Anatomy of DAF

 
1. Stilling Chamber 
The Stilling Chamber provides an opportunity for the surge of influent water to be dampened. Once dampened, the flow is directed to the surface of the DAF tank by the Stilling Chamber Baffle allowing the influent water to be equally dispersed along the width of the DAF for subsequent treatment.

2. Recycle System Saturation Chambers
VanAire’s exclusive Saturation Chamber design is the heart of our superior aeration technology. Compressed air is injected into the recycle stream on the discharge side of the recycle pump. The resulting air/water mixture flows into the saturation chamber, where it is exposed to tremendous turbulence. This turbulence is used to maximize the amount of air that dissolves in the recycle stream. The Saturation Chamber also separates any undissolved gasses from the recycle flow, eliminating the disruptive effect that these undissolved gasses have on the DAF Clarifier.

3. Pumps
VanAire Aeration Units utilize heavy-duty, single stage, centrifugal pumps for simplicity and long-term durability. To allow many years of maintenance free operation, our pumps feature wear resistant duplex stainless steel internals, a stainless steel dynamic shaft seal as well as stainles steel impellers and pump housing. VanAire introduces compressed air on the discharge side of the recycle pump so the pump is not exposed to the erosive effect of pumping water with entrained air. 

4. Breakout Valves
VanAire’s exclusive Breakout Valve design creates the most effective DAF bubbles in the industry. This design creates the violent, high-shear action necessary to release the dissolved gasses as microscopic bubbles. All wetted parts are stainless steel with diaphragms of Nitrile with other diaphragm materials available including Viton.

5. Skimming Mechanism
The concurrent top skimming mechanism and the continuous support of the float by our aeration maximizes float density and minimizes the settling of previously floated contaminates. VanAire offers corrosion resistant fiber reinforced polyester chain. Stainless steel type 304 or 316 chain is also available.

6. Plate-Pack
An optional and exclusive cross-flow plate-pack and a second stage of aeration can be located near the midpoint of the DAF clarifier. This plate pack provides a damping effect on the water in the DAF, and provides a surface for the coalescing of bubbles and microscopic particles. As the bubbles and particles build up on the underside of the plates, the particles agglomerate into larger particles, eventually floating to the surface. Our cross-flow design does not affect the normal flow patterns in the DAF; so hydraulic loading rates are not affected.

7. Settled Solids Removal
Settled solids are moved from the bottom of the DAF tank using an auger system or angular false bottom which allows solids to be hydraulically removed through drain valves that are manually opened or automatically opened via electronic timers or through the PLC program. An optional bottom skimmer system is available to skim the solids through the end of the DAF tank, up a dewatering ramp (above the water line) and into a sludge hopper. The bottom skimmer system is also controlled by an electric timer or through the PLC program.

8. Beach-Float Hopper
The concurrent skimming mechanism pushes the float up the inclined beach plate. An adjustable time delay feature is included to pause the top flights on the beach, allowing free water to drain from the float.

9. Overflow Weir
Allows the working level of the DAF Clarifier to be manually adjusted to position the waterline properly on the beach.

10. V-Notch Weir
A V-notch weir is standard on all VanAire DAF systems for flow rate indication.  Electronic flow rate indication is available as an option.

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